Hiccups

Basics

Description

  • Sudden, involuntary contraction of the diaphragm (usually unilateral) and other inspiratory muscles terminated by abrupt closure of the glottis
  • Medical terminology: Singultus
  • Usually occur with a frequency of 4–60/min
  • Most episodes are transient and self-limiting
  • Chronic hiccups can impair eating and drinking, leading to weight loss, dehydration, and electrolyte imbalances
  • Involves a reflex arc with afferent, central, and efferent components:
    • Afferent: Irritation of the sensory fibers of the vagus and phrenic nerves:
      • Common triggers include gastric distension, GERD, CNS disorders, respiratory irritation, medications, temperature changes, stress, excitement
    • Central: The hiccup center involves multiple structures within the brainstem, particularly in the medulla oblongata, periaqueductal gray, and reticular formation, and the upper spinal cord
    • Efferent: Motor fibers of the phrenic and vagus nerves generate the characteristic diaphragmatic contraction
  • Classification:
    • Hiccup bout: <48 hr:
      • Typically benign, self-resolving, and often caused by a common trigger
    • Persistent hiccups: 48 hr–1 mo:
      • May indicate an underlying medical condition such as GERD, infection, or neurological dysfunction
    • Intractable hiccups: >1 mo:
      • Frequently associated with serious medical conditions, including central nervous system disorders, malignancies, or chronic metabolic derangements
  • Male > female (4:1)
  • More frequently observed in older adults

Etiology

  • GI:
    • Gastric distention, overeating, eating too fast
    • Esophageal: Gastroesophageal reflux, achalasia, candida esophagitis, cancer
    • Gastric: Ulcers, cancer
    • Hepatic: Hepatitis, hepatoma
    • Pancreatic: Pancreatitis, pseudocyst, cancer
    • Bowel obstruction
    • Inflammatory bowel disease
    • Cholelithiasis, cholecystitis
    • Appendicitis
    • Abdominal aortic aneurysm
    • Postoperative, abdominal procedure
    • Gastroparesis
    • Esophageal distention from procedures
    • Aerophagia often seen in anxiety, hyperventilation, or excessive gum chewing
    • Subphrenic abscess
  • Diaphragmatic irritation:
    • Hiatal hernia
    • Intra-abdominal mass
    • Pericarditis
    • Eventration
    • Splenomegaly, hepatomegaly
    • Peritonitis
    • Thoracic surgery/trauma
    • Diaphragmatic tumor
  • CNS:
    • Vascular lesions: Ischemic/hemorrhagic stroke, head trauma, arteriovenous malformations
    • Infectious: Encephalitis, meningitis, abscess
    • Structural: Cancer, Parkinson disease, multiple sclerosis, hydrocephalus
    • Ventriculoperitoneal shunt
  • Thoracic:
    • Infectious: Pneumonia, TB
    • Cardiac: MI, pericarditis
    • Aortic aneurysm
    • Cancer
    • Mediastinal lymphadenopathy
    • Pulmonary embolism (reported as a rare cause)
  • Head and neck:
    • Otic foreign body irritating the tympanic membrane
    • Pharyngitis
    • Laryngitis
    • Goiter
    • Retropharyngeal/peritonsillar abscess
    • Neck mass
  • Metabolic:
    • Uremia
    • Hyponatremia
    • Hypocalcemia
    • Hypokalemia
    • Hypocapnia
    • Gout
    • DM
  • Toxic/drug induced:
    • Alcohol
    • Tobacco
    • Dexamethasone
    • α-methyldopa
    • Benzodiazepines
    • Steroids
    • Barbiturates
    • Narcotics
    • Chemotherapeutic agents
    • Antibiotics
    • General anesthesia
  • Psychogenic causes:
    • Stress/excitement
    • Malingering
    • Conversion disorder
  • Idiopathic

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